High Voltage Power Supply Polarity Switching Overshoot Control
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Solution Overview
Problem
Conventional high-voltage power units using reed relays face challenges in quickly switching polarity, leading to increased ion non-detection periods and reduced analysis accuracy in mass spectrometers, especially when actual output voltages are lower than rated outputs.
Innovation Solution
A high-voltage power unit with a controlling unit that adjusts the output voltage of both positive and negative voltage generating units to minimize overshoot, using a feedback loop with voltage limiting to ensure rapid and stable polarity switching, even at lower output voltages, by gradually decreasing the positive voltage and rapidly increasing the negative voltage during polarity transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-voltage reed relay is used to switch polarity, then the relay can change contacts to switch polarity, but the switching time increases due to the need to decrease voltage before switching
Solution Approach 1:
The system prepares both positive and negative voltage generating units in advance, with each unit capable of independently generating its respective polarity voltage. The controlling unit pre-configures the appropriate voltage generating unit based on the required polarity, eliminating the need to decrease voltage before switching and enabling immediate polarity change.
Solution Approach 2:
The patent introduces a dual voltage generating unit system where one unit generates positive voltage and another generates negative voltage. These units act as intermediaries that can be independently activated by the controlling unit, avoiding the need to switch contacts on a single voltage source and thereby reducing switching time.
2Reliability
If voltage is decreased before relay switching, then relay damage is avoided, but the ion non-detection period increases
Solution Approach 1:
The system pre-configures the appropriate voltage generating unit based on the required polarity, eliminating the need to decrease voltage before switching and enabling immediate polarity change.
Solution Approach 2:
The patent replaces the mechanical relay switching system with an electronic control system that directly switches between positive and negative voltage generating units. This substitution eliminates the mechanical contact switching process and the associated voltage decrease requirement, enabling faster polarity changes without compromising protection.
3Speed
If the output voltage is lower than rated output, then the voltage switching speed should be maintained, but excessive overshoot occurs in conventional systems
Solution Approach 1:
The controlling unit monitors the output voltage of both positive and negative voltage generating units and adjusts their output accordingly. When switching polarity, the controlling unit detects voltage deviations and dynamically adjusts the generating units to minimize overshoot, ensuring stable voltage transitions even at lower output levels.
Solution Approach 2:
The system dynamically adjusts the output of the voltage generating units based on real-time conditions. The controlling unit modulates the voltage generation process to match the required output level, preventing excessive overshoot while maintaining fast switching speed across different operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for rapid and accurate switching of high-voltage polarity, reducing ion detection non-periods and improving analysis accuracy in mass spectrometers, even when operating below rated output voltages, by preventing excessive overshoot and ensuring prompt voltage stabilization.
Implementation Method 1
a booster transformer T1; a drive circuit 3 for driving a primary winding of the booster transformer T1
Implementation Method 2
a rectifier circuit using a Cockcroft-Walton circuit composed of four capacitors C1 to C4 and four diodes D1 to D4
Implementation Method 3
an operational amplifier 11; a Zener diode 17 connected between an output terminal of the operational amplifier 11 and a reference potential
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3A~3B
AI summary
An excessive overshoot preventing unit (16) is connected to a loop in which a command voltage Vf according to a difference between: a voltage obtained by dividing an output voltage Vout as a high voltage; and a control voltage Vcont set from the outside is obtained and fed back to each of drive circuits (3 and 5) of a positive voltage generating unit (2) and a negative voltage generating unit (4). The excessive overshoot preventing unit (16) clamps the command voltage Vf at a voltage value according to the control voltage Vcont. An overshoot that occurs in the voltage generating unit (2 or 4) at the time of polarity switching mainly depends on a circuit constant, and hence the amount of overshoot is excessive in the case of a low-voltage output even if the amount of overshoot is optimal in the case of a rated output. To deal with this, in this power unit, the overshoot of the command voltage Vf is suppressed by the excessive overshoot preventing unit (16), and hence the output voltage can be promptly settled to a target voltage even in the case of a low-voltage output.